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What is the Beggs/Mueller emergency spin recovery technique?
I've always used PARE for spin recovery:

Power to idle
Ailerons neutral
Rudder opposite the spin until rotation stops
Elevator forward to break the stall

What is Beggs/Mueller emergency spin recovery, and why does it work?
Does it work in any aircraft?

I was always taught that the E was "Elevator nose down to break the stall" and the dive recovery was a separate thing once the plane is flying again, but as long as you get the plane into a dive you've done the hard part :)

yes, i wrote it wrong, and will fix.

Who are Beggs and Mueller?  I’ve been flying almost 40 years and thought this was called “hands off”…

P.S.  Spin recovery techniques are aircraft specific so it may be wise to mention this.  (ours used to be stick full aft...)

From the fine folks over at EAA, the Beggs/Mueller technique (also sometimes called the "hands-off" spin recovery technique) is:

Power – Off. (presumably they mean "to idle", and not "stop the engine")
Remove your hand from the stick.
Apply full opposite rudder until rotation stops.
Neutralize rudder and recover to level flight.

So essentially the same technique as PARE, except instead of neutralizing the ailerons & pushing the nose over you put your hands in your lap:

Power: to idle
Ailerons: Put your hands in your lap.
Rudder: Full opposite the direction of spin until rotation stops.
Elevator: Your hands should still be in your lap!

The big advantage to the Beggs/Mueller technique seems to be that with your hands off the stick there's no chance of the pilot panicking and yanking back on the stick/yoke and prolonging the spin.  It's predicated on the fact that the nose will fall naturally in a stall, breaking the stall and putting the plane into a slight dive.

I can't say as to whether the Beggs/Mueller technique will work in all aircraft, but it should work in any plane that tends to naturally recover from a stall (i.e. one where the nose naturally falls when the plane is stalled) and has otherwise-conventional spin recovery characteristics. That covers every plane that immediately comes to mind, but it's possible there are some with a canard configuration where spin recovery isn't conventional, and the Beggs/Mueller technique may also not be ideal.

I'm still interested in why it works

@rbp The mechanics are essentially the same as PARE - they're variations on the same technique. The rudder is still what's arresting the spin, and Beggs/Mueller counts on the aircraft's natural tendency to "want to fly" to take care of the rest rather than making it something the pilot does and risking incorrect control inputs making things worse.

The Beggs/Mueller technique is:

engine idle
let go of the stick
push rudder against spin direction

This was developed for pilots of the Pitts Special biplane and will work well with naturally stable, powered aircraft. With gliders (where it strictly doesn't apply) it will be less effective, but still work in most cases. The better way is to combine both, rudder against the spin and stick forward (your PARE technique), but only until the rotation stops. Then both the stick and the rudder must be neutral until speed is sufficient for the pull-out. Beggs/Mueller is more about avoiding wrong inputs due to confusion than ending the spin in the most direct way.
Spin recovery with the hands off the stick will be slower than with active control input. If the control surfaces are free-floating, natural stability is normally less than what it is with fixed control surfaces. For that reason, the Beggs/Mueller technique is less effective than actively ending the spin with both rudder and elevator. If the pilot does not realize he is in an inverted spin, pushing down will make matters worse, however.
Why rudder against spin direction?
An aircraft spins because something stabilizes both the rotation and the high pitch angle. First the rotation: This is caused by fully separated airflow on the retreating wing while some section on the advancing wing has attached airflow. The high drag on the retreating wing pulls this side of the aircraft backwards, while the lift on the section of wing with attached airflow pulls that side of the aircraft forward. Remember, airflow is mostly coming from below, and the spin motion modifies the local flow direction the more one moves away from the center of the aircraft.
Why elevator forward (Back in inverted spin)?
Now the pitch angle: The center of rotation is ahead of the wing in the forward fuselage. The masses in the forward fuselage produce little centrifugal force, while the masses in the rear fuselage and the tail, having a substantial distance from the center of rotation, produce a substantial centrifugal force which pulls the whole aircraft into a level attitude. Since the aircraft's motion is mainly downward, this inertial moment increases the angle of attack above the stall angle.
To break the spin one needs to end the rotation or the pitch attitude. Since they mutually reinforce each other, one must be ended to end both. On aircraft with long fuselages the rudder is more effective to stop the rotation, while on aircraft with long wings the elevator will be more effective in ending the spin via reducing pitch attitude. The rotation is then stopped by the roll damping of the wing. Using both together will give the best effect, however.
Why engine to idle?
Having some added dynamic pressure on the vertical tail will also help to end the rotation, but then the aircraft will pick up speed very quickly. Setting the engine to idle will avoid falling into this particular trap, but again for the price of a somewhat slower recovery. Sometimes an aircraft needs that added dynamic pressure to end the rotation, so Beggs/Mueller will not work in all cases.
But keep in mind how the Boeing 307 prototype crashed, killing the KLM evaluation commission and several Boeing employees. Asymmetric power was used because the small vertical would not end the spin and caused an overspeed event with subsequent structural failure. So make sure to first try ending the spin with engine idle.

@qqjkztd: The fuselage should ensure that some of the accelerated air still hits the vertical, but some displacement from the center of prop wash must be expected. This displacement, however, is more in vertical than horizontal direction due to the falling motion of the spinning plane, the more so the flatter the spin is. Also, the prop operates in a vey high angle of attack region where the blades are stalled on the way down and see large variations in dynamic pressure. Its efficiency will is likely less than half the normal value in a spin. Yours would be a good candidate for a new question.

To answer the part of the question around whether it works for all aircraft, it is important to note that the Beggs/Mueller technique doesn't work for all aircraft, and that you should refer to your POH/AFM to understand the specific techniques that are relevant to the aircraft you are flying.
As an example, this accident report refers to a crash involving a Cessna A150 Aerobat which apparently will not recover from a spin with the Beggs/Mueller technique.
https://www.atsb.gov.au/publications/safety-advisory-notice/ao-2021-025-san-001/

At the York Soaring Association (northwest of Toronto) we mainly use a Schweizer 2-32 for spin training, which is mandatory for all pre-solo student pilots, as well as advanced spin training for our pilots in the aerobatic training program.  The 2-32 was also known as the X-26 Frigate in NASA's astronaut training program and was used as a platform for what they called 'yaw/roll coupling' training. I.E. it spins like crazy!  As an aerobatic instructor I've spun the 2-32 many times and the Beggs-Mueller recovery works well in this a/c.  However, we stress that pilots review and be familiar with the spin recovery technic of the particular aircraft they will be flying and use the recommended spin recovery method in the POH for that aircraft.  Also, that they NEVER intentionally put an a/c into a spin that is not certified for spins!  Many glider POH's are pretty sketchy about spin recovery and in that case I would recommend the standard Transport Canada ( or FAA) spin recovery technic.  Finally, be especially anal about the weight and balance calculations of your aircraft before doing spins. One other thing; we take high tows for spin training (about 1 mile above ground) because multiple spins can chew up a lot of altitude very fast. Our hard deck for recovery is 2,000 ft. agl, which is not only air law in Canada but just plain common sense.  Done properly and safely spins are uber fun and great training exercises.

Hi, Don, Welcome to Aviation.SE! This answer is interesting, but it doesn't really seem to answer the specific question of what the Beggs-Mueller spin recovery technique is. Could you perhaps add a paragraph describing the technique? On SE sites, we want all answers to actually answer the specific question that was asked, though including additional relevant information such as you've given here is certainly fine. For more information, see [answer] and the [help]. Again, welcome!

As a flying instructor and CFI many years ago (50 actually, rather embarrassing isn't it), I taught spin recovery on Beagle Pups, Cessna Aerobats, Victa Airtourers (Australian aerobatic aircraft),Tiger Moths and Blanik sailplanes.
The technique in those days was that you should hold the stick back whilst applying full rudder, as with some aircraft if the stick was not fully back the elevator could blanket the rudder.
During my time as an instructor, my brother bought a Tiger Moth and so I taught him to fly it. I was predominantly training pilots in spam cans at the time and in teaching my brother spins, the Tiger reminded me that it was NOT a spam can, with particular regard to the fact that it has virtually no fin in front of a massive rudder. So much so the if you applied full left aileron and full right rudder the Tiger would roll to the right. The rudder had more roll power (secondary effect of rudder) than the ailerons.
So, to demonstrate spin recovery in the Tiger, I put it into a right hand spin, talking my brother through it, "Stick back, opposite rudder. . . " only to have the Tiger recover instantly come out of the spin and enter a spin the other way, to the left.
That's one mighty powerful rudder.
The subsequent recovery from the left spin was made with full right rudder and the stick moving forward.
The episode reminded me what my maths teacher said when I got an algebra problem wrong,"It's not so important to get the right answer, as to understand the method".
You live (hopefully) and learn.
Pete.
PS. The Boeing 747 stall recovery (in the Sim) was also a very enlightening exercise . . . if you are interested.
Pete.

I suspect it was less the rudder than the dihedral which made the Moth roll. Of course the rudder is needed for the sideslip, but once that is established, dihedral causes the roll.

Agreed.A combination of

A combination of Dihedral, Blanketed wing, Retreating wing with lower airspeed.

Gene Beggs calls this the ‘Emergency Spin Recovery’ and it is specifically for Pitts Specials. He says “After cutting the power and releasing the stick, the pilot has eliminated any concern about whether the spin is upright or inverted. With the hand completely removed from the stick, it is impossible to make an error in control input. It is impossible to reverse the spin with rudder. It is impossible to transition from upright to inverted or vice versa. The Emergency Spin Recovery involves no reference to flight instruments. The pilot must decide only whether to use full left rudder or full right rudder. When trying to determine which rudder pedal to use, these are important points to remember. You must look down the top of the engine cowling at the ground so you will always see yaw in the correct direction. You should see the fuel cap in your field of view. The recovery rudder pedal will be displaced closer to you when you take your feet off both pedals. [when both pilots have their feet off - Forbes] When you push this pedal, it will travel farther and be harder to push….”
Even in types other than Pitts Specials the above actions are a good start in an emergency and or where there is confusion and disorientation. After that, while still holding absolutely full anti-spin rudder, if you find the stick/yoke ‘locked’ aerodynamically, manually put it where it should go. If it is displaced rearwards push it forward and vice versa. Remember the type specific actions you should know like the Chipmunk needing up to full forward stick to stop an upright spin, the in-spin (roll component) aileron needed in Extras and maybe some other types with full-span ailerons and the white dot painted in the instrument panels of some Yaks indicating where to put the stick.

Welcome to aviation, one answer is sufficient and can be updated using the edit link. Your (aggregated) answer would benefit from some formatting (specifically, paragraphs)

Eric Muller was a Swiss architect who was very active in aerobatics in the ‘70s and ‘80s. He won Swiss and European championships and was well known around the world. He wrote a book on aerobatic techniques (with Annette Carson) ‘Flight Unlimited’ in 1983 which was updated in 1995 by Ms Carson after Eric’s passing in 1990 which was medical, not aviation related. It is a good book (and is still available) and the chapter on spins is comprehensive, going into great detail about tail configurations and the best elevator positions for spin recovery because of them. In short, there can be significant shielding of the rudder by the tail plane and elevator in upright spins in some aircraft which can be made worse by forward stick applied prematurely. The primary anti-spin control is full rudder opposite to the yaw as seen by looking down the top of the engine cowling. Jamming the stick fully forward in some aircraft will not only shield the rudder and delay recovery but can rapidly transition the upright spin into an inverted spin. Try it in a Pitts! It is called a ‘Crossover Spin’.
Gene Beggs was a Texan flight instructor who built a Pitts S1 (‘72-‘77) so he could compete in higher classes of aerobatic competition. He was almost killed twice in his Pitts after getting into spins inadvertently, in fact dozens of people were killed as a result of not recovering from spins in Pitts Specials. Gene took a keen interest in spins and really took notice when he read an article about recovery written by Muller, which suggested that the best method to recover from an inadvertent spin especially if there was any confusion about whether the spin was upright or inverted was to “Close the throttle, let go of the stick and apply full rudder opposite to the yaw”.
Beggs tried this in his Pitts and knew that he had found the solution to a problem that had been plaguing the aerobatic scene in the USA, which was dominated by the Pitts, and had been really gnawing at him. He devised a spin training course and wrote a book ‘Spins in the Pitts Special’ which is still available. There is no spin in the Pitts that will not recover by this method. The controls trail in the airflow (elevators nose up, ailerons into the roll) until the yaw stops and then the stick snaps into the centre by itself.
However, after initially not wanting to talk about other types, people came to him and Gene subsequently flew many types and found that in some aeroplanes, in some upright spins, the elevators would stay locked in the stick back position and take some force to get forward. Right spins in the T6/SNJ/Harvard was one example, the turbine-engined Beech Mentor was another and the humble Cessna 150 was another. There are probably more…
To finish, let me say that the correct spin recovery actions are type specific. eg the Chipmunk (where the tail plane and elevator do not shield the rudder) needs progressive forward stick, right to the stop if necessary and hold it there. Also check pre aerobatics that the park brake is fully off or rudder bar movement can be restricted. The Extra will not recover from some fully developed spins without ailerons into the roll component ie opposite to the anti-spin rudder when upright and the same side as the anti-spin rudder when inverted. Do your research, get competent instruction in two-seaters by Old Hands and Wise Heads. Happy Landings.


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How does an organization decide to evacuate planes (e.g. in a hurricane)?
I recently became aware that Embry Riddle temporarily evacuated Florida to escape an oncoming hurricane, taking dozens of planes with it. How does an organization like this decide that planes are at significant risk of damage and shouldn't just be tied down in a storm?  I would think tying down a plane and especially hangaring it would be good against any storm that isn't hurling debris or knocking down buildings.  How bad does the weather have to be to decide to move all the planes?  Do airlines similarly remove all their airplanes from airports in a hurricane's path?

A line of Embry Riddle's plane's parked at Auburn, taken from Auburn's Facebook page.

But a category-whatever hurricane is a storm that's "hurling debris and knocking down buildings"!

I was watching these planes on flightaware leave the airport. :D

Related: How Well can an airplane which is tied down be protected from a blizzard, the first answer has a nice picture of what can happen to a tied down airplane.

Planes are also more fragile than buildings. If a tree branch is blown into your house at high speed, you may have damage, but the house might well not be uninhabitable. If a tree branch is blown into a small aircraft, it may well do much more damage, but you're certainly not going anywhere until a qualified person does an inspection, and the repairs won't be nearly as simple.

This can be dependent on a few things. For larger organizations like airlines resources may not be an issue (they generally have pilots needed to move the planes). For smaller organizations it may come down to a few factors. First off do you have the people needed to move the planes (and how will you get them back home). Do you have anywhere to put the planes provided you do move them, you will need tie downs else where not to mention its going to cost you to store them elsewhere. On that note, can you foot the bill for such a move (not only the planes but the fuel, pilot housing or return trip etc...). If you want to see some of the damage and thought process for smaller planes check out this thread on the recent hurricane.
Often airlines will cancel inbound flights in advance of a hurricane so there will be fewer airplanes turning around at a potentially effected airport anyway. For the planes parked there (for what ever reason) they may they may simply move planes out of the airport,

Airlines are moving some planes to hangars while flying other planes
  out of the area entirely until the storm is over.

FWIW commercial airframes are fairly transient by nature anyway, so as long as its not the location of a hub city the planes are in and out anyway.
While they have access to way more resources it looks like the Airforce moves planes appropriately.
As to what conditions lead to this decision its hard to say and ultimately up to the operator in question. Generally I would think they would err on the side of caution. But from a purely economical standpoint (potential damage aside) its may be more cost effective to move the planes and use them elsewhere than have them sit on the ground anyway (since the airports will be closed).

can you foot the bill for such a move? -- Many insurance policies will cover "evacuation flights" to get out of the path of a hurricane if you're based in an area where that's a concern. It may not cover all of the costs(I'd have to look but I think my policy is $500 per "evacuation" & a max of $1000 per year), and there are usually some caveats like a minimum distance you need to fly away from your home base to qualify as "relocating", but it can help.

That is quite interesting I did not know that. Do you know how common that is across policy providers? Does it depend where you are based out of?

I've never seen a policy that didn't have this provision, but all the policies I've seen are east-coasters who are at least occasionally in the path of hurricanes. Folks in the midwest may have other weather provisions. The amounts of coverage and the distance you have to reposition vary ("75 miles, to an area not covered by a hurricane warning or watch" is common), and if you don't reposition to get away from the storm your deductible is modified (higher) because of the higher risk.

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What's required for a plane certified to fly to Antarctica?
What special features besides the obvious long range does a plane have to have to fly to and land in Antarctica?  I know not just any plane can make the trip, but I couldn't find many relevant regulations or certification requirements.
It seems like the C-17 and LC-130 are some of the most popular for these flights, based on the "US Antarctic Program Inter-agency Air Operations Manual" and this site. The manual does list other aircraft that can use Pegasus White Ice Runway: "C-5, KC-135, C-17, C-130, LC-130, P-3, A-319, and smaller aircraft".  I also know the Basler Turbo BT-67, DeHavilland DHC-6 "Twin Otter" aircraft, and C-141 are traditional polar operations planes.
The only applicable regulations I could find were:

In VOLUME 3   GENERAL TECHNICAL ADMINISTRATION, CHAPTER 29   PROVING
AND VALIDATION TESTS, 3-2438       CLASS II NAVIGATION AUTHORIZATIONS
D.4) North Polar (OpSpec/MSpec B055) and Antarctic Airspace
(OpSpec/MSpec B050). Applicants proposing to conduct terminal area
operations within these areas must conduct validation flights. No
requirement exists for validation flights for those applicants
conducting overflights if previously authorized in OpSpec/MSpec B036
and B040. During validation for approval of overflights of these
areas, test teams should include in-flight planning, contingencies,
CNS requirements, “fuel freeze” procedures, cold weather altimetry,
applicant’s reaction and passenger recovery plan, and emergency
airfield procedures.
Airplanes must have enough fuel to reach an off-continent alternate
if they arrive and cannot land.
I also remember reading somewhere that these aircraft had to have
fuel temperature and/or manual fuel level indicators to help prevent
fuel freeze.

So what special features or parts does a plane need to make an antarctic trip besides long range?  Why are c-130's and DHC-6's perfect for this kind of mission?
Note: Obviously pilots also have to have very specific and special training for Antarctic missions, but I'm focusing on the planes themselves in this question.

Image source

I can't answer the complete question. But at least I can give hints on the key topics, as unpaved runway certification and ETOPS in the case of twin civil aircraft. Finally you are mentioning military aircraft, which might be certified by a significant number of different regulators (actually as many as countries), so your question might be kind of big

legal or technical requirements? And if legal under what country's laws? Technically all you need is enough range and engine power (the winds down there can get very strong). And if you want to land and return safely anti-icing, rough field landing gear (preferably skis), etc.. Legally, depends on the country but probably more than that.

The Boeing 757 (Royal New Zealand Air Force and Icelandair) can fly there too.

I'm not aware of any specific 'certification' for aircraft operating to/from Antarctica. The air operations to/from Antarctica varies greatly depending on the location of the airstrip and season.
Actually, there are airports in Antarctica that can handle 'conventional' aircraft (atleast seasonally), like the Union Glacier Blue Ice Runway, which has been certified to handle commercial flights. US Army CRREL Report 93-14, Notes on Antarctic Aviation identifies three broad flight categories:

Long trans-ocean flights to and from well developed Antarctic airports.
Medium-range flights to and from short substandard Antarctic runways with limited facilities.
Long trans-ocean flights to and from expedient runways that are rough or soft.

According to the type, the aircraft requirement can vary significantly. For example, for the first case, (long range) civilian and military aircraft maybe more than enough. From the same report:

For flights of the first category, exemplified by Christchurch to McMurdo in springtime, any conventional trans-oceanic transports, civilian or military, should be satisfactory as long as they have adequate useful range, with the ability to reach an alternate or to return to the point of departure, arriving with standard IFR fuel reserves.
For medium-range flights to and from short substandard Antarctic runways with limited facilities, the aircraft can be smaller, but it has to be capable of safe over-ocean journeys, with appropriate range and engine-out performance.
For long trans-ocean flights to and from expedient runways that are rough or soft, the aircraft requires both long range and robust, high-flotation landing gear.

The report also lists the desirable characteristics of aircraft for operations in Antarctica, which should explain why aircraft like C-130 and DHC-6 are used the most:

General configuration: High wing; high engines; tee-tail or high tail; low belly; spacious flat-floor fuselage; large doors (tail ramp,side hatch, swing nose).
Engines: Multi-engine; gas turbine (free turbine turboprop; turbojet or turbofan).
Landing gear: Wide stance; short legs; low ACN/LCN; large tires; soft tires; multi-wheel, multi-unit assemblies; large wheel-well fair ings (for big wheels or ski retract).
Speeds: Reasonable cruise speed; slow approach; low stall and landing speed.
Robustness: Strong airframe, tolerant to vibrations; reliable engines and fuel system; rough-field landing gear; good hydraulics; instruments, avionics and electrical systems resistant to vibration.
Maintainability: Easy access to problem areas and parts that need frequent changes; spares inventories based on failure probability, easy troubleshooting; access to additional spares at reasonable speed and cost

You can see where this is going. The aircraft used in Antarctica are varied, with anything from C-17 Globemaster IIIs to re-manufactured DC-3s in service, De Havilland Twin Otter being one of the most popular. You can see that most of the aircraft operating from there are high wing aircraft with excellent STOL capability. The report also lists some of the aircraft most suited for operations in Antarctica.

Aircraft with characteristics that are appropriate for Antarctic internal operations; Image from CRREL Report 93-14, Notes on Antarctic Aviation by Malcom Mellor
Most of the aircraft look similar with high wing with wide, short landing gear and multi-engined. Quite a few of these are excellent STOL aircraft too. Obviously, they will be modified with the required navigation equipment and long range fuel tanks (for example, with long range fuel tanks, the range of Basler BT-67 is extended to ~4000 km).
Operating in semi prepared fields require the aircraft to be equipped with skis- like the Lockheed Martin LC-130J. These aircraft have the provision for carrying out JATO operations. A number of smaller aircraft (like the Basler BT-67) are equipped with skis as well.

LC-130 skis, By NSF Contractor - US Antarctica Program Common Share Servers, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5883002
Aircraft operating in Antarctica should also consider the effect of air operations on the fragile and unique environment. The long range of aircraft come in handy as this limits the need for holding fuel reserves at the Antarctic airport, reducing infrastructure requirements and ecological impact.
The aircraft operating to/from Antarctica have, in addition to the usual requirements, items like onboard stairs:

The A319CJ is designed with ultra-long range tanks, enabling the aircraft to return safely to its original port without the need to land and refuel. .... Skytraders limit the need for extensive ground support infrastructure by equipping its aircraft with specialist remote field functions such as its onboard stairs.

Though quite a few types of aircraft can (and have been) operated in Antarctica, it should be noted that not all of them are equal. A good example would be the conclusion of the inquiry into RNZAF Boeing 757 that landed below published minima at Pegasus Field in 2003:

... a whiteout landing. However, in the event of this occurring the likelihood of injury was significantly greater for the Boeing 757, with its long landing gear supporting low-slung engines on a low wing, than it was for the Hercules with its rough-field landing capabilities

This, in addition to the additional navigational aids (TACAN) fitted in the C-13Js. It should be noted that RNZAF still flies 757s to Antarctica.

With regards to the A319CJ: airstairs are a standard option on the A320 family. (Not sure if they still exist as an option on the A320neo?)

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Why the lack of faster piston-powered planes?
There aren't very many fast piston airplanes in production. By "fast" I mean, if you look back in the early to mid 20th century, before turbines won out, there were lots of piston airplanes in production that pushed the practical velocity limit of propeller-driven aircraft, cruising 360+ knots in military planes, sometimes as fast as 330 knots in commercial airliners. And this was with a terrible understanding of aerodynamics and piston engines compared to today.
Today, for both singles and twins, the fastest speeds around aren't much higher than 200 knots. ~240 knots in the case of the very fastest couple available airplanes like the Cessna 400 and fastest Mooney.
There are indications that with modern materials and engineering, much faster speeds can be achieved using piston engines already available. The Cobalt CO50 Valkyrie design claims to push a spacious 4 person cabin up to 260 knots with a single 350hp engine. The recently-certified Diamond DA-62 can move a spacious 7 passenger cabin at ~200 knots using only a pair of 180hp engines.
Why aren't there more faster piston airplanes available? Would the market not be interested in piston powered planes that could do 300 knots? Shouldn't you be able to make almost those speeds for a very small plane powered by a single commonplace 350hp engine? Shouldn't you be able to make those speeds in a more spacious plane with a pair of commonplace 350hp engines?
My understanding of the marketplace is that the #1 reason people choose piston is cost. And isn't the cost of operating piston engines, even two piston engines versus a single turboprop, much much lower? How much does a 350hp turbocharged piston engine cost brand new, 50k-60k dollars? So even buying a pair of them is 100k-120k dollars. And then how much does a single comparable turbine engine cost? ~800k dollars with proportionately higher rebuild costs per flight hour? Plus 20%+ higher SFC than a piston?
Basically, I see the Piper M600 listed at 2.8M USD, or the TBM930 listed at 3.9M USD, and I don't understand why it would be hard to achieve nearly the same performance for a fraction of the price using a pair of cheap piston engines. For example the Piper M350 has the same 6 passenger cabin as the M600 and also includes pressurization, and with a single 350hp engine makes over 210 knots on a very old airframe with a list price of under 1.2M USD. If you basically built the same airplane but reoptimized for twin engines and using modern materials and aerodynamics, shouldn't you be able to achieve near 300 knots by adding another piston engine? And shouldn't you be able to sell the resulting airplane for well under 2M USD and with a significantly advantaged SFC and therefore range and payload than the M600?

Look at the ownership of the planes. The owners of these planes are on the most part GA pilots who just want to fly for fun, so they don't need a plane that fast (There are a few exceptions though).

Below 10,000 feet there is a 250 knot speed limit imposed by the FAA.

@RonBeyer that's interesting although aren't many in-service piston-powered airplanes capable of flying efficiently near and above 20,000'? My understanding was that this is the case even for many piston planes aren't even turbocharged, much less pressurized. Also, I did mean to use the word 'dearth' although maybe you are right, 'death' will attract more attention :)

@Charles847 "...shouldn't you be able to achieve near 300 knots by adding another piston engine?..." Unfortunately, props don't work quite that way. A propeller can only go so fast, so adding another one won't necessarily make a plane go faster.

The power requirement of an airplane grows with the cube of speed. When you fly fast with an airplane which needs to comply with a set minimum speed imposed by regulations, your drag coefficient is nearly constant, so flying faster does two things to a propeller aircraft:

Drag goes up with dynamic pressure, which is proportional to speed squared
Thrust goes down with the inverse of speed.

Power is thrust times speed, so if the the 350 hp get you to 210 knots, doubling the installed power can only bring you to 264 knots. A turbine can still make limited use of the increased dynamic pressure by ram recovery, so here the thrust decrease over speed is not quite as bad as for piston engines.
Expressed in an equation, the power $P$ demand for a given speed $v$ is:
$$P = \frac{D\cdot v}{\eta_{Prop}} = \frac{\rho\cdot v^2\cdot S_{ref}\cdot c_D\cdot v}{2\cdot \eta_{Prop}} \rightarrow v = \sqrt[\Large{3}{}]{\frac{2\cdot P\cdot\eta_{Prop}}{\rho\cdot S_{ref}\cdot c_D}}$$
If you want to fly fast with better efficiency, you need to increase the minimum speed - note that the landing speed of many fast piston aircraft was around 100 mph. Now you need a long runway, and for operation in bad weather or at night infrastructure for instrumented approaches, and you will end up at airports where turbine fuel is easy to get and cheap, but piston fuel will be hard to find and expensive.
As with all expensive machinery, you need to use it often to justify the expense. Now your fuel cost will factor in, and will make a piston engine rather unattractive.
Fast piston aircraft were only built while turbines were not yet available. As soon as turbines emerged, all fast piston designs were obsolete. And aerodynamics in the early 1940s were already very advanced; engineers back then built airplanes which would be impossible to design with the engineers of today. Back then, they got fully manually controlled airplanes into the air when today everyone would refuse to do it without hydraulic boosters at only half the flight speed. They could design cooling ducts which actually increased thrust, an art which is (almost) lost today.

Thanks for including the basic math! Would you mind expounding on that a little more? I am thinking that speed^2 = X units of power. So in your example you would do (210kts)^2 = 44,100 units of power, so a plane with double the power would have 88,200 units of power, and then take the square root to get the speed of the double-power plane. But that doesn't quite add up or account for your point #2.

@Charles847 Start with power = thrust * speed.  When flying level at constant speed, thrust = drag, which means that power = drag * speed.  Finally, drag = (constant) * speed^2, which gives us power = (constant) * speed^3.  So, if we double the power we only increase the speed by the cube root of two (about 1.26), and 1.26 * 210 = 264.6.

Interesting point about maximum required stall speed and its effect on the airfoil design.. but suggesting that aeronautical engineering 'used to be better' because they did things when they had no alternatives that today's engineers would consider...inadvisable... is silly.

@Daniel I feel sorry for you if you cannot appreciate the elegance of an ingenious and simple mechanical solution and think an added layer of system complexity which introduces a host of new failure modes and maintenance headaches, not to mention additional weight, is better. But you are in good company.

@jjack Thanks for the vote of confidence. It seems obvious to me that the state of the art is much better now, because we make aircraft that perform much better, not worse than what came before, in every single category of aircraft-- from gliders to hypersonics. The humans that came before were just as smart as we are, but they didn't know as much and their tools weren't as good.

Also, turbine engines, in a pinch, can burn practically anything that flows and that burns without producing solid particles in the exhaust stream (although you won't get performance as good as with the fuel(s) that the engine is optimised for); piston engines are much, much pickier fuelwise, and tend to show their displeasure by doing annoying things like seizing up or exploding.

Why can't a piston engine with a suitably-designed intake take advantage of ram compression?

@Sean They can, but due to their instationary air intake they are less efficient. Roy LoPresti tuned Mooneys such that one propeller blade would sweep over the intake  manifold just when one cylinder valve opens. That alone added a few knots in top speed.

@Daniel I agree. Sure during WW2 they were fast at churning out new airplanes, yet if anyone made an airplane today that had the same failure rate, they would go to jail for gross negligence, and rightfully so. A lot of engineering efforts goes in the direction of simplifying things, notable examples being the invention of the 2-stroke engine following the 4-stroke engine by 20 years, or cracked connecting rods.

@PeterKämpf Why would the efficiency change that much - the stagnation pressure remains the same, and the biggest losses of the flow in the piston engines occur at throttling cross sections - namely the throttle, maybe a bit in the carburetor (if there was one), and at the intake valve.

@CarlBerger Please explain your comment better - I did not talk about engine efficiency. I guess you wonder about ram recovery - with a continuous process the higher pressure can be utilized much better than with the discontinuous process of a piston engine.

@PeterKämpf, I'll try. Ultimately you argue that a steady state process is more efficient than a cyclic one, that may be due to better design point optimization. Yet, the turbo diesel engines I saw had a large air box (Ladeluftsammler) for trying to maintain a constant pressure at upstream of the intake ports, ram-air itself would achieve just that. Upstream of the air box the system is a lot more steady state already. Ram air just being a constant higher inlet pressure, I don't see why a turbo charged IC engine with quasi-steady-state inlet should benefit less than turboprop.

@CarlBerger You are right, the more precompression by a turbocharger is added to the piston engine, the more the process resembles a turboprop. The transition is fluent.

A piston means a propeller, and a propeller is more efficient at lower altitude and much less efficient at higher altitudes (that's part of why there are variable pitch propellers ). But the converse applies to jets, which is why you don't really see jets cruising around at 5000 ft.
A piston engine is pretty complex and has quite a few moving parts that are moving in a somewhat violent fashion. A piston changes direction every stroke, and the combustion that drives each stroke is a different force and purpose than that of a jet engine. Those dynamics change a bit with the type of engine (a rotary engine is different than an inline engine), but it still requires a combustion to force a piston to push a propeller to drive the aircraft. The mechanics are much more complex than a jet engine (which essentially just brings air in, compresses it, lights it on fire to Bernoulli it, and uses that exhaust to turn the compressors [usually]). (I found some nifty engine animations at http://www.animatedengines.com)
Also, propellers and jets move an airplane differently. A propeller is no different than any other airfoil. Its primary mode of motion is by decreasing the pressure on one side, causing movement towards that lower pressure. A prop feels like a big fan, but most of its motion is pulling the aircraft. However, a jet functions by pushing the aircraft. Because of this difference, a propeller can reach its upper performance limitation at a slower speed than a jet will. Again the converse applies and a jet can reach its lower performance limit at a slower speed than a prop will. This allows a turbine engine to fly faster.
Lastly, a piston engine will likely weigh more than a comparable turbine engine. And in an airplane, weight makes a difference in pretty much everything.

Two older posts, but do a good job of the breakdown in differences: http://www.planeandpilotmag.com/article/turbines-vs-pistons/#.V6JwlUYrKCg http://www.shorelineaviation.net/news---events/bid/50442/Piston-Engine-Aircraft-vs-Turboprop-Engine-Aircraft

a rotary engine is different than an inline engine Did you mean radial instead of rotary? Since you're contrasting it with inline

The propeller efficiency will not suffer with altitude as long as the propeller is large enough. The highest flying subsonic aircraft were all propeller driven.

@TomMcW Sorry, meant radial. Though both still function with pistons to make a propeller turn rather than generating thrust by moving air through the engine.

@PeterKämpf Efficiency and ability are different though. Just because of the nature of air, at altitude a propeller blade will have to turn faster to generate the same thrust at higher altitudes. Just like a wing is less efficient at altitude. 80,201 is impressive. Bigger props may have allowed the aircraft to move faster so that it could generate the lift to make it to 80,202. But you'd also need bigger engines to turn those bigger props faster. It's a huge balancing act.

If you want a fast propeller-driven aircraft, it's much easier to use a turboprop engine than a large piston engine.

the turboprop is lighter and more compact
it produces less vibration
it produces less noise
it's more reliable (the moving parts count drops from thousands to tens = less to go wrong)
it's easier to build a high-performance turboprop. Late WW2 piston engines operated at the edge of what was possible at the time. They needed special high-octane fuel to prevent detonation (and even then, backfires were somewhat common on e.g. the Griffon).

I agree with your sentiment.  We can effectively take general aviation into jet territory by using existing piston tech.  There absolutely is an opportunity to capitalize on where the M350 leaves off.
IMO, it is not with a twin, but a more powerful (at altitude) and more efficient engine than the TIO-550.  Making the M350/Malibu into a twin would give you a Piper Navajo, which for the cost of doubled operating expenses, you get no increase in speed and only two additional seats.  The two nacelles kill a lot of the power benefit.
I'm convinced the answer is a diesel, possibly two stroke, with some serious forced induction.  Displacement need only be enough for takeoff requirements, so a 550 ci engine or smaller may suffice for a six-seater; but with FI and two stroke, it could reach serious altitudes, speeds and savings.
Personally, I love the M350/Malibu because it is the only pressurized piston single (with club seating), cruising at almost 250mph at 20gph.  Even an interim solution could be for a company to develop some STCs for a larger diesel conversion, with FI as icing on the cake.  It may add weight, but it would cut the fuel consumption in half, and Jet-A is an additional savings.  Taking some of the old Malibus and upgrading the interior, avionics and giving a diesel engine may cost $1M for a big package deal but it would make for a more desirable aircraft than a new M350.
The possibilities with forced induction are under appreciated.  Aeromomentum Engines show what can be done with a small engine block.
As for people on here saying power requirements vary with the cube of the velocity - that does not add up.  It should be the square, and the figures for the Piper M Series reflect that.  213kts(600hp/350hp)^1/2 = 278kts For max cruise, Piper advertises 213kts for the M350 and 274kts for the M600, so accounting for possible rounding in performance specs or maybe cruise altitudes, this is right on.
Anyway, rather than wasting the time of talented engineers on electric planes and flying cars (that would be impossible to keep airworthy or insure with fender-benders), we just need a certified FI diesel and then we can produce planes with jet performance for M350 prices and DA-50 operating costs... done.

"I'm convinced the answer is a diesel, possibly two stroke, with some serious forced induction" so basically a turboprop ;)

@sophit certainly not. Low power gas turbines have pretty bad efficiency compared to piston engines. SFC data is quite hard to find, what I found on jet-engine.net indicates that turboprop engines below 500kW struggle to get better than 0.35 kg/kWh, truck diesel engines in that power range are better than 0.2kg/kWh

The big picture is unfortunately very different.


text:
Are seaplanes allowed to taxi in residential areas?
There's a small pond/lake behind my house. A sea plane was just going around it. It was very loud and got like 10 feet from the shore. It's just going in circles and won't take off and leave.
This is at the tiny town of Elbow lake, MN. There's a small airport here, Elbow Lake Municipal (Y63). If you look at the links, you can see it's near a small lake, and there is a large peninsula on it that comes to a point.
It's so annoying. How can they do this, so close and in residential? Isn't there some regulation to prevent this?

Note: The town of Elbow Lake, MN should not be confused with the body of water, Elbow Lake located some 70 miles NNE. That lake does have a seaplane base (M49), but that area is entirely unrelated to this question.

Related: If I have a float plane, can I land on any body of water?

There is a marked, FAA approved Seaplane base right at the point you're describing.  You're probably completely out of luck:  https://skyvector.com/?ll=47.143014169585676,-95.52892874114967&chart=4&zoom=1

how is it approved when it's within the 500ft limit?

An airplane cannot fly within 500ft people/buildings, unless it is intending to takeoff or land.  As you have described it, this plane is not flying (it is taxiing in circles around the lake).  If it does takeoff, that will also be legal.  If it were to fly past your house at less than 500 ft, without the intention to takeoff/land, then that would be a violation.  That is not what you have described.

@kelly  What would you do if it had been a boat, busy boating about making the same level of noise ?

To answer the title of the Question: Yes, floatplanes do fly over residential neighborhoods in urban areas. Ex: floatplanes daily depart & arrive the waters of Lake Union in downtown Seattle, flying quite close over the residential neighborhood of Wallingford.

Legally speaking, a seaplane on the water is a boat. If it's legal for a boat to be there it's legal for the plane to be there.

If you have concerns over the safety of what is going on, here is what you should do:

Record a video with your phone. Try to get the N number (it should be painted in large letters on the side of the aircraft).
Record the date/time and your exact location where you shot the video from.
File a report with the FAA, preferrably by calling the hotline number.

The FAA will investigate the operation for the legality of it. If this is legal depends on a number of factors. Most local jurisdictions have control over the use of a body of water for sea planes.
Usually as far as the FAA is concerned, once a sea plane is on the water it is considered a boat. You may also have to call your local natural resources department.

+1 for "Usually as far as the FAA is concerned, once a sea plane is on the water it is considered a boat". Reasonable possibly but still funny.

And, in most places in the US, they can be as loud as they want until the 10pm noise curfew.

I know in my state, state police control waterways, they may be able to help you.  I called the HiPo once on a stunt pilot causing near accidents, and erratic driving while buzzing an interstate.

A sea plane was just going around it. It was very loud and got like 10 feet from the shore. It's just going in circles and won't take off and leave.

As has been pointed out in other answers and comments, if the aircraft is taking off or landing, there are no regulations requiring distance from persons or structures, at least that I know of.
What you may be witnessing is an attempt to takeoff in less than optimal conditions. For example, if there is no wind and the surface of the water has no wave action, it can be very difficult to break away from the water sufficiently to get the aircraft "up on the step", in other words to get it going fast enough that it can plane along the front part of the floats (or the hull). Once the floats are "planing" on the water, with the lesser drag than if they are fully in the water, the aircraft may then be able to accelerate to takeoff speed.
The usual procedure if you're having trouble taking off from a wave-less water surface (often called glassy water), is to run back and forth at a high power setting with as much speed as you can get to generate waves. Then, at some point hopefully, as you run back across waves you've previously generated you'll be able to break free of the water because there's less drag running across waves, even small ones (ripples even) than glassy water.
I had to employ that procedure a few times back when I was flying floats, and I remember one instance when it took at least a half hour before I managed to get airborne.

Are seaplanes allowed to fly in residential areas?

I can't speak to current practices and regulations as I retired in 1999. However, back in the 1970s and 1980s when I was flying floats, we often operated in residential areas. For example, go to Google Earth and bring up Eugene, Oregon. Look at the area on the Willamette River immediately adjacent to downtown Eugene. You'll notice two bridges. We often operated alongside residental areas upstream and downstream of the bridges. We also operated between the bridges. Depending on conditions that sometimes meant flying under one of them, not an uncommon practice for seaplanes, and perfectly legal, at least back then.
If you don't have Google Earth, you can use the Google Earth browser version or see it on Google Maps.

I must see that 747 on floats.

@dotancohen That would be an interesting concept, but there was no overlap between my float plane flying and 747 flying. I didn't start flying 747s until 1990. But in the 1970s and early 1980s I belonged to the CAP. We had a J-3 with an 85 hp Continental engine. In the winter we kept it on wheels, in the summer on floats. I was one of two instructors in the squadron, and each summer brought a raft of CAP pilots wanting to get their seaplane rating. There's nothing like instructing in an airplane with marginal performance to get you to really learn things.

There's no regulation that forbids all seaplane usage near the shore in all residential areas.  After all, in many jurisdictions your neighbor can moor their seaplane right on their shore if he fills out the right paperwork.   As others have noted, seaplanes can operate similarly to boats when taxiing.  There appear to be no local restrictions applicable to boating operations in Elbow Lake.  There is a seaplane base at the nearby airport, Y63 or "Elbow Lake-Pride of the Prarie Seaplane Base", so of course seaplane operation on those lakes is permitted under some circumstances.
While I am not aware of any restrictions on proximity to strutures while taxiing, Generall FAA regulations require that it remains 500 ft from any person, structure, or vessel while not taking off or landing (or taxiing).  Minnesota regulation requires taking off and landing in such a manner as to clear all structures on the land by at least 100 ft and to clear all boats or persons on the water by at least 300 ft vertically and horizontally or "as near to 300 feet as the area of the water will permit". (source).
Some areas have noise and operating hours restrictions, but your lake does not appear to be on the list of lakes in Minnesota with operating hour restrictions.  Even if it was, exceptions may be made for private or personal seaplane bases.  I can't find any other noise regulations for your area.
The reality is, you live next to public water and the water is not a protected park or your private sanctuary.  What you see as a charming lake for relaxing and enjoying the view, others may view as a great area for noisy swimming, boating, and yes, seaplane operation. You can designate up to 2,500 square feet of swimming area that boats and seaplanes can't enter (see The Minnesota Boating Guide), but even then the water is public water.  Being mad about noise and reckless behavior from a seaplane to me is akin to being mad about noise and reckless sports in a community park. In both situations you can check local noise and usage regulations and even call the authorities, but what's going on probably isn't illegal even if it is unusual and rude.  This sounds more like an interpersonal matter than a legal matter and should probably be handled as such. Keep in mind that the seaplane operator could be a neighbor down the street struggling to take off on a fishing trip and make sure your response is based on an honest assessment, not outrage.

Unless the aircraft is actually taking off and landing, it is required to maintain 500 ft from any person, vessel, vehicle or structure (47 CFR 91.119).

The question suggests that the plane is taxiing on the lake, not flying.  So the 500ft. rule should not apply.

right at the point of my land, the lake gets really narrow. so when the aircraft does take off (it didn't today, but it has) they surely can't be over 500ft from the shore. it would be impossible.

"Unless actually taking off or landing":   It is OK to get within 500 ft. of land when taking off; it is problematic to simply fly close to the ground without the intention of landing.

@Kelly the rule referred to is 500 ft vertical from the surface when in the air. It does not apply to aircraft taxiing (imagine how that would work at a major airport, if aircraft had to stay 500 ft away from terminal buildings etc.)

So there is no regulations for noise volume or being too close if the plane isn't in the air. that seems a little strange. I mean, it makes sense what you're saying, but it seems like there should be some kind of regulation. I thought the plane was going to crash right into the shore. it was so close, the wings touched the willow tree branches...

We are not saying there is NO regulation covering this; we are saying there is NO FAA regulation.   You'll have to look to your local and state (non-aviation) agencies for Boating Rules and Noise Rules.  But we won't have that kind of local info here.

authors: Bob Jarvis - Слава Україні


text:
Is it centrifugal force that allows a non-aerodynamic body to achieve lift purely because of thrust?
If a body has a greater than one thrust to weight ratio, then is the centrifugal force acting perpendicular to the Earth's gravitational pull that allows it to fly ?
Or are there other forces that I am not aware of being at play here ?

Further Clarification
So, when a body is moving on the surface of the Earth, we can assume that it adheres to some semblance of circular motion.
Any body in circular motion will experience an outward force perpendicular to the direction of motion.

So, given enough thrust, can any body fly because of the centrifugal force created against Earth's gravitational force ?

I don't think I get what you are trying to say. Can you please clarify it?

I think they're trying to ask "Is it possible for something that is not capable of producing Bernoullian lift in addition to Newtonian lift to fly, given enough thrust", to which the answer is "it may not be 'flying' but it will go through the air!"

It's basically a question clarifying the force acting on, say, a rocket or VTOL aircraft - they're confusing centrifugal force/centripetal force, and the idea of any other force counter-acting gravity

@SMSvonderTann I have updated my post.

It depends on what you call "flying". If flying is gaining altitude with the force of the air (aerodynamic lift), then the centrifugal force has nothing to do with flying or aerodynamics. It's rather orbital mechanics based on gravity. Air in this case is not a requirement, orbital mechanics works in space, not flight.

I'm voting to close this question as off-topic because it belongs either to physics or space exploration.

The question title is an oxymoron. If the object is non-aerodynamic then it can't produce lift at all because lift is an aerodynamic force. I agree this is off-topic

@TomMcW Really ? Won't a >1 thrust/weight ratio create lift in any type of object ?

All upward acceleration is not necessarily lift. Lift is specifically an aerodynamic force. Rockets create no lift whatsoever. They accelerate upward purely due to thrust.

If the question is how a "non-aerodynamic body" (does this actually mean "non-lifting body"?) with thrust > weight can avoid falling to the ground, it is very simple: orient and/or configure the vehicle so that the direction of its thrust is straight up or nearly straight up, and the thrust will overcome gravity. Now, 90% or more of the lift-drag-weight-thrust diagrams you may see will show thrust horizontal, but that's because they're (usually) depicting ordinary winged aircraft in level flight. The kind of vehicle you describe is very different.

Basically, you're asking 'Can you achieve orbital velocity in atmospheric conditions?'.
Orbital velocity is approximately equal to
$$v_o \approx \sqrt{\dfrac{GM}{r}}$$
which, if we fill it in at Wolfram.alpha, yields a velocity of almost 8km/s (yes, per second), or almost 18000mph, or a Mach number of 23.23.
The current speed record for sustained atmospheric flight is just shy of 2200mph (which, interestingly, stems from 1976 and was set by the SR-71 Blackbird). This means we're still a factor 8 short. Since drag is roughly proportional to the square of your velocity, this means we're a factor 64 short of thrust on a similarly designed airplane. But I think by that time you'll be running into all sorts of interesting exotic effects, not the least of which is that your airplane will desintegrate by the massive amount of compressive heating (basically, you're doing a 'sustained' orbital re-entry maneuver in a much thicker part of the atmosphere).
The answer is then, hell no. Not as long as Earth has an atmosphere.

Note: if you're asking about vacuum conditions, then the figure you're looking for is delta-V, not thrust-to-weight ratio. The delta-v of your craft must exceed aforementioned orbital velocity. Your T/W ratio doesn't come in to play at all.

It is not centrifugal force that allows a non-aerodynamic body not designed to be aerodynamic to achieve lift by harnessing the energy from thrust unless it is going so fast that it is in orbit.
If an object is moving fast enough, it would eventually get to the point where it would be in a low orbit; in that case I suppose you could say it is the centrifugal force keeping it at that height (orbiting), and of course, the lower it is the faster it must move, and the more thrust is required to counter the air resistance.
Typically when we talk about something moving through the air, the thing providing a constant height would be the aerodynamic force acting on it.  Even a brick can fly aerodynamically by creating lift from striking air molecules if it has enough thrust to keep its speed high enough to do so.
It is still due to the air's Newtonian action-reaction on the object. Unless of course, we are talking about vertical flight, in which case the lift comes from the Newtonian action-reaction from the thrust, not the air.
I don't mean to exclude thrust vectors here.  Of course, the angle of thrust will play a part even when there is Newtonian aerodynamic lift.
If you're talking about orbital properties, check this out in the space section of SE.

So, given enough thrust, can any body fly because of the centrifugal
  force created against Earth's gravitational force?

Yes, but it would be called orbiting, not flying.

I've updated my query. I think I'm using centrifugal force in the incorrect context. But could you tell me why my reasoning is wrong ? Thanks.

@SanjeetSuhag The more I gather on your question, it sounds like you're asking if the reason something that isn't designed to be aerodynamic can fly is because it is essentially in a low orbit.  If you set the conditions so that it had zero lift by changing its angular orientation to the relative wind as it passes through the air, eventually, yes it would be in a high-air-resistance, low orbit if it were going at the correct speed for that orbital altitude, which would be very very fast if it were still in the lower atmosphere.

So, I'm incorrect in my usage of the circular motion in this context, right ?

@SanjeetSuhag No, not necessarily.  Centrifugal force certainly keeps any object at a constant altitude at the right speed even with 0 aerodynamic lift.

"Yes, but it would be called orbiting, not flying": There is a big difference. Flying requires constant energy (thrust) to be converted into lift to fight gravity. Orbiting needs no energy, and no lift (Newton's 1st law).

@mins Even at zero aerodynamic lift, there would be form drag.  The thrust would just be an extreme example of low altitude orbit correction.  Even satellites experience some minor air resistance from some of the particles floating around up there and require thrust adjustments from time to time. This is just an extreme example of that when there is no lift being created, and obviously this scenario is purely hypothetical.  No one would put something in such a low orbit that it requires a rocket behind it to keep it going.

@RyanMortensen: I see what you mean, and I'm not trying to say it's wrong, but the two quantities of energy have nothing in common. Voyager 1 & 2 continue their orbital trips for now 38 years without propulsion. CMG can be used to change attitude without thrust. The lunar trip was essentially a non-powered orbital trip (except for orbit injection).


text:
What does the solid black star symbol on this VNC chart mean?
On the Canadian VNC there are symbols, the meaning of I can't quite figure out. In the Nanaimo aerodrome there are several "star" symbols. The unfilled one shows the location of the aerodrome beacon. What do the other solid black star symbols mean?

The one circled in red reads "S2 Fl R 209". Based on my knowledge of marine lights I thought that it could describe a red flashing light. The star symbol, being in an aerodrome could mean "limited hours" but even then, I'm not able to make sense of the rest of the description.
What does the solid black star and "S2 Fl R 209" mean?
EDIT: According to the CFS, the solid star is a hazard beacon light. Not sure how to decode the text.

Interesting. The coordinates for 209 indicate that it's somewhere in Victoria and 295 is west of Penelakut Island. Geographically close to, but not exactly where the solid star symbols are located.

CFS says the solid star is a hazard beacon light.

Some info on the abbreviations: https://en.m.wikipedia.org/wiki/Light_characteristic

Here's how to decode S2 Fl R 209:
S1 - Identifier. Bearing relative to an aerodrome (N, W, NE). If there are multiple with the same bearing, they are numbered
Fl - Light pattern
R - Color
209 - Elevation
Source

The hollow blue stars are for airport beacons.
The solid blue star at an airport indicates part-time operation.
Your question was on the solid black stars, and those are used to denote hazard beacons.
ref: http://www.flysifc.ca/docs/CAPGEN.pdf  page 38


text:
What are some alternative benefits to electric propulsion?
The context I am asking is regarding if electric motors could ease the fuel cost, take off weight, or runway length if they were set up in 'hybrid' configuration with regular hydrocarbon engines.
If so, could potentially a military aircraft (IE, F35) have any weight savings or feature benefit of having an electrically boosted STOVL/VTOL system? Any fuel savings over regular flight? And of course, would this make sense at all from an engineering standpoint, today or ten years from now?
I am not asking the ability of electrical propulsion systems to replace the current main prop or jet systems, but rather to the alternative capacity that they might offer in other auxiliary or backup uses.

Considering that the energy density of hydrocarbon fuels is significantly greater than that of batteries, its a lot "cheaper" to add a little horsepower than it would be to install electric motors, battery banks, and associated controls, especially when most of the time you are just going to be carting around extra weight, and extra fuel to do it, along with reduced payload. Until battery density comes closer to fuel, it simply isn't going to be a good replacement or augmentation vs a little extra fuel consumption.

Also http://aviation.stackexchange.com/questions/26910/could-an-electric-engine-provide-the-same-performance-as-jet-engines-on-current?rq=1

I don't agree this is a duplicate. The suggested duplicate is asking how it would be done while this asks why, and whether, it should be done, which is not really discussed on the other question.

When you say "auxiliary" use, you're thinking of a powered wheel for taxiing or, if it could spin fast enough, a take-off boost by spinning up the MLG wheels, or something like that?

For aircraft, none.
Hybrid drive trains are used because:

They offer, rather limited, efficiency improvement by being able to operate the engine closer to its optimal conditions.
Because spark-ignition engines are more efficient at higher power settings, the hybrid can get advantage by having smaller engine, running it at (relatively) high power or not at all and cover the variations in required power using the electric engine.
Cars accelerate and stop a lot and often cruise at small fraction of power, so they can make good use of this.
The advantage only applies to spark-ignition, i.e. gasoline, engines. Compression-ignition (diesel) engines have more uniform efficiency over their operating range, so there is no or only negligible advantage. Which is part of the reason you don't see hybrid diesel cars.
Batteries can be pre-charged with cheaper mains power. This is used in the hybrid cars, but it obviously requires lots of heavy batteries.
Electric motors can provide high torque from standstill. Piston engines can only provide limited torque from standstill and it stresses the clutch heavily.
This is particularly important for train engines. Train wheels have bearings lubricated by oil pumps attached to the axles that only operate when the train is moving, so when the train is stopped, the bearings are not lubricated and the force required to get it moving is much higher then when moving.
At high power outputs, electric generator and motor are simpler and more reliable than a gearbox and clutch. For big train engines and ships, mechanical clutch is out of question. Hydraulic one, which is a turbopump and turbine in oil, can be used, but that still needs variable gearbox. The electric drive-train acts as almost ideal continuously variable transmission, being able to deliver almost constant power over wide range or rotational speeds.

In either case the hybrid drive-train is heavier than mechanical one.
Now for aircraft:

The engine is run at constant speed and power setting, which is relatively high (usually cruise setting is 75% for piston and even higher for turbine planes). So there is no room to design a hybrid drive train to run the engine closer to optimal.
Weight is critical for aircraft, so the weight of electric generator and motor is a show-stopper there. For cars adding weight causes smaller increase in drag, so its less of a concern and trains even need to be heavy to have enough adhesion for their traction.
Since weight is critical, aircraft can't afford to take much batteries that could be pre-charged with cheaper mains electricity, the other benefit hybrid cars have.
Propellers need almost no force to start spinning and are operated at narrow range of RPM, so the ability of electric motor to provide torque from standstill and across wide range of RPM is of no use to aircraft.

So none of the benefits for which hybrid drive trains are used in other vehicles is applicable to aircraft, so there is no point in building one.

I agree with the previous answer that there are a number of issues with implementing a serial hybrid (e.g., a chemically powered generator running electric motor(s)) on an aircraft, but I think there are a couple of positive sides to it as well...though we may have to design a new propulsion system rather than supplement an existing one.  I found a NASA study looking at distributed turboelectric propulsion to replace cryogenically stored hydrogen scramjets on a BWB aircraft which shows the potential to actually save weight by moving over to the electric system (https://mdao.grc.nasa.gov/publications/IPLF08-Kim.pdf), but that's a pretty niche application.  This, naturally, does not universally imply that that is the case, however: just for now and for that application.
However, the mention of distributed propulsion does highlight a major plus for electric propulsion systems.  It's dramatically easier to route flexible power lines than mechanical shaft connections.  Hence, if you want to have multiple engines...electric propulsion enables you to do that relatively easily.  Also, say that you want to make an aircraft that can hover and cruise as a typical fixed wing aircraft -- typically, you'd have to design collective pitch change into your proprotors.  Or, with electric propulsion, you could just have a bunch (I mean 12+) of proprotors, each of which you tailor with a twist distribution proper to a certain mode of flight.  Look at a proposed NASA design (http://aero.larc.nasa.gov/files/2012/11/Distributed-Electric-Propulsion-Aircraft.pdf), a separate design by Aurora Flight Sciences that has advanced in the DARPA X-Plane program (http://www.darpa.mil/news-events/2016-03-03), or Lilium Aviation's recent design (http://lilium-aviation.com/).  Given all of these are concepts, so nothing is proven by a working design as of yet...but it seems like a lot of people are looking into the possibilities afforded by a distributed electrical propulsion system.  The expected advent of lithium-sulfur batteries should be a big deal here too.  These batteries are expected to have a capacity of ~500 kWh/kg (about 2x the absolute best Li-poly available now), but I think that 2019 is the expected date for high-capacity Li-S batteries to start hitting the market.
Finally, one thing about engines is that their efficiency can vary dramatically depending on how they are being run (i.e., the load on the engine, RPM, etc.).  This excerpt from a German textbook is, unfortunately, in German (https://books.google.com/books?id=QAGHZPVnnSAC&pg=PA540#v=onepage&q&f=false), but the basic idea is reflected on a Wikipedia page where the plot is reproduced in English (https://en.wikipedia.org/wiki/Consumption_map).  On the vertical axis is power output of a spark-ignition engine, the horizontal axis is the RPM that the motor is being run at, the the contours are, essentially, fuel consumption.  The long and the short of it is that, if you have any change in the engine's load or what RPM it's running at, it's not running at its most efficient.  This would be the case for your typical non-hybrid propulsion, where load and RPM vary with flight condition.  However, if we decouple flight condition (i.e., desired cruise speed, throttle setting, prop speed setting, prop pitch setting, etc.) from the chemical engine and let an electric motor (which has a much higher efficiency than a chemical engine) deal with these variations, we can, conceivably, run the chemical engine within an optimal performance range (some variation will probably be needed if power output is excessive, but that's a design problem wherein you'd try to size the engine for its most efficient in cruise, I'd think).  That's a fuel savings for us, plus a decrease on engine wear because it doesn't have to see all the throttle variations typically present in normal flight.
As noted, this isn't the case for a typical airplane (small RPM bands)...but what if we decided to play the game that Aurora, Lilium, and NASA are playing and make VTOL/STOVL aircraft?  The differences between flying a proprotor in edgewise and axial flight are dramatic, and having RPM control can make a lot of difference and might obviate a need for variable pitch propellers.  Just design your twist distribution right, vary your RPM, and you just might be able to get acceptable efficiency in both regimes (at least for slower speeds).  Or, like NASA, use two different sets of proprotors for a fixed-wing cruise and vertical flight, each one optimized for that specific flight regime.  I'm not saying it's easy...just that electric propulsion makes the opportunity present.
But, yes, weight and technology are major concerns...and you can see in the electric aircraft that have been built to date.  Firefly (Sikorsky's electric helicopter) has a max endurance, I think, of 15 minutes.  Helios (https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-068-DFRC.html) is a neat aircraft, but look at how flimsy the design is in order to enable it work as a solar/fuel-cell hybrid (i.e., solar just doesn't provide a lot of power, so you need to make a light, high-aspect ratio aircraft).  The Gamera-S is a solar-powered quadcopter under development at the University of Maryland (see below), but look at how sparse the frame is--weight is a HUGE problem for these aircraft, especially given how much power we can currently get from batteries or the sun.  Serial hybrids don't get rid of that problem (since it introduces engine weight, fuel weight, lubrication system weight, etc.) but it can give you a couple of perks, as noted above.

How do you think is “about 2x the absolute best Li-poly available now” going to change the game? The difference in specific energy between best Li-pol battery and Jet-A is 2 orders of magnitude!

It's true, and I wouldn't expect Li-S batteries to immediately cause a revolution because of that.  However, I'm looking at the potential, especially for small manned/unmanned aircraft (or, even with that NASA report where the weight of other items such as cryogenic storage for another low-density fuel drives up your fuel system weight).  Examples in the potential GA realm would be the e-Genius (essentially a motorglider--http://www.ifb.uni-stuttgart.de/egenius/index.html) or the E-Fan (a more typical aircraft--https://www.youtube.com/watch?v=lavvVN7fSEU).


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What are the odds that I'm the next most qualified pilot on a given flight?
On a given flight, let's say a commercial flight with about 100 passengers and a few flight attendants, what are the odds that I (or any other individual) am the most qualified person to fly the plane, after the pilots?
I call myself a pilot very loosely here. I fly paragliders (so I trust my own life to my flying skills, and know a little bit about airspace, etc.), I've flown lots of simulators, RC aircraft, and have started ground school, but haven't yet done any actual flight in powered aircraft.
I'm sure many aviation enthusiasts and non-commercial pilots have thought about a scenario where the pilots of their flight are somehow incapacitated. Maybe someone frantically gets on the PA and asks if anyone knows how to fly a plane. I've wondered if I should even speak up in that situation? (should that be a separate question?) I'm not a great choice to fly the plane, but what are the chances that I'm the best we've got?
I guess to generalize the question, what are the odds that a given person on a flight has some reasonable level of flight experience?

We all can dream, can't we? But reality will turn out different: https://aviation.stackexchange.com/questions/8986/can-a-passenger-realistically-replace-suddenly-incapacitated-pilots

Peter, I like your answer on that one think that's probably right about panic (but, I don't think panicking people would necessarily prevent someone from reaching the flight deck, they'd scream, but would they leave their seats?) and also agree that the flight crew wouldn't ask that question, but what if they felt they had no other option? This question differs from that one though, it asked if a completely inexperienced person could fly based on radio instruction alone. I'm not completely inexperienced, though admittedly, pretty close.

Mins, I know there is no real answer for this. But maybe something along the lines of "2% of the general population hold a private pilot license, so on a flight of 100 people, odds are that two are private pilots, which would make them more qualified than you" except, I don't know the right numbers.

This sounds a bit like you're asking how likely United Airlines Flight 232 is.

When people ask about the usefulness of PC flight simulators when learning to fly, I think about how useful would a PC bike simulator be when learning to cycle.  If a paraglider is analogous to a high performance mountain bike here, the airliner would be a Harley.  Yes, you know about handling and flight dynamics for paragliders and RC aircraft, but not for big iron.  You won't know the systems, the operating procedures etc.  The crewmember who tried to save Helios 522 had a CPL but couldn't work out how to turn the radio on

Dave, the crew member of Helios 522 went into the cockpit and after one minute, the engines ran out of fuel. No time to do anything, especially with low Oxygen. Remember that he had not a B737 type rating. A flight simulator (with good add-on aircraft) can massively help on how the different systems (not handling) work on that aircraft.

Although off topic, this is easy to calculate in an approximation, if you can find the relevant data. If you can find the numbers of people who hold a license that would make them more qualified than you - say an ATPL - you can work out the probability that one is on your flight (making the approximation that your flight companions are random selections of the population). Repeat this for all the categories you can think of that might be better than you - commercial pilots, GA instructors, instrument rated pilots, multi-engine pilots etc. Find the chance that one of them is on your flight.

"2% of the general population hold a private pilot license,"  I think it's far less than that.  In the US for example, last number I saw was 619,000 pilots, out of a population of 340 million - my math puts that as 619,000/340,000,000 = 0.182%.  So I'd say that You're odds at being the most capable are more like 1/number of passengers, if you consider yourself capable. Otherwise, the math says next to none, more like 1 person out of every 5 to 6 flights might have a pilot rating (unless there are deadhead pilots on that trip).

CrossRoads, that's basically what I was looking for, thank you. In hindsight, I could have searched out the numbers and done the math myself, as DJClayworth suggested. For Dave Gremlin, aren't certain flight simulators certified for actual flight training? I think I even heard that some airline pilots train exclusively in sims (I'm sure they have previous flight experience). I've seen a video of someone who used only PC fight sims for training and then completed a take-off, flew a pattern, and landed, with no major mistakes or input from the flight instructor that took him up on his first try.


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What are the most powerful airplanes that ever flew?
This question What are the least powerful airplanes that ever flew? made me wonder what the most powerful manned airplanes are that ever flew. There are two sensible categories, I suppose:

Most thrust overall.
Best thrust-to-weight ratio.

EDIT in response to a comment by @ratchet freak:
Answers including rocket-powered aircraft are welcome, although I'm also interested in other propulsion systems. However, I'd like to exclude rockets by requiring the craft in question to be able to at least land on, if not start from a runway.

EDIT 2 in response to a comment by @Robin Bennett:
I'd like to restrict this to reusable craft, in the sense that they should be fine to go again with not much more than a refuel. So I guess that excludes the Space Shuttle.

do rocket engines count? what about unmanned?

@ratchetfreak Good points. In the spirit of the original question, I would exclude unmanned aircraft. Rocket engines are a little tougher. At what point does something stop being an aircraft and become a rocket?

@PerlDuck it has only two engines, it won't be it.

@Antzi Yes, that's why I removed my previous comment. Maybe the An-225 with her 6 x 230kN = 1380 kN?

Does the space shuttle count? (12GW, 20,000kN, 3:1 thrust-to-weight)

@RobinBennett ah man, all these things I didn't think about :-). I guess the orbiter itself counts, but I'd like to exclude detachable boosters, i.e. the craft should be reusable.

@RobinBennett the re-usable part of the shuttle needed the external tank to fire its main engines. Even empty, the tank adds 40% mass, giving the Shuttle a smaller TWR than the X-15. — If we're really going to consider re-usable rockets here, then the winner is probably the SpaceX Falcon 9 first stage, with 8.8 MN thrust and a spectacular TWR of 40:1. Non-reusable rockets can of course give much higher ratios yet.

@user35915 would it be reasonable to limit the scope to air-breathing vehicles only?

@dalearn well I've already allowed rocket engines, so I guess it's a little late for that. But like I said, I'm interested in all sorts of propulsion systems. So far there's no answer for piston engines, for example...

Air Force One when it is The Air Force One. With thousands of jets, thousands of nukes, hundred of subs and dunno how many troops it is definitely most powerful aircraft.

"the craft in question to be able to at least land on, if not start from a runway." Well, the Me-163B Komet (Luftwaffe) did take off and land from a field, so that ought to count. It had wheels for takeoff (dropped) and a skid for landing. No Mother Ship used. I would exclude anything launching straight up or using a Mother Ship.

@user35915 "Rocket" is a characteristic of the kind of design, not size; rockets are defined as carrying all the reaction mass onboard.

@chrylis-onstrike- did I make size a defining characteristic for a rocket anywhere? If so, that was not my intention. My point was more that one could argue that the X15, e.g. is a rocket and not a plane. Which is why I included the "land on a runway" thing.

@PhilPerry sure, the Komet would clearly count. Its characteristics are, by modern standards, not that impressive, though.

@user35915 It was in a deleted comment.

Most thrust overall?
Well the most powerful aviation gas turbine to date is the GE90-115B, producing a whopping 115,000 lbs of thrust per engine at maximum static thrust settings.
Overall the aircraft with the greatest thrust to date has been the StratoLaunch.  With 6 PW5406 engines, each rated at 56,000 lbs of thrust, this gives it the highest takeoff thrust at slightly over 340,000 lbs.  For production aircraft, it’s the A380.  With 4 84,000 lb thrust class Trent 900s, it gave the jet a massive 336,000 lbs of thrust on takeoff.  This beats out even the AN-225 Myria, with its 6 Progress 6DT engines rated at 51,600 lbs each.
The most powerful turboprop still goes to the old dog - The Tu95 Bear.  With four Kuznetsov NK-12 turboprop engines, each rated at 15,000 shp, no other turbopropeller came close.
The honor for the highest powered piston driven aircraft goes to the Hughes H-4 Hercules.  The ‘Spruce Goose’ was driven by 8 Pratt & Whitney R-4350 Wasp Major engines at 3000 bhp, giving it 24,000 bhp at full throttle.  This is also a sobering demonstration of the huge power to weight advantage of gas turbines over reciprocating engines.  Consider that the Tu-95 mentioned above has half the number of engines yet still packs 2.5x the power of the Spruce Goose at full throttle.
The gas turbine powered airplane with highest thrust to weight ratio that I ever heard of was a stripped down Su-27 used by the Soviets in the 1980s for setting time to climb records, similar to the F-15 Streak Eagle program.  The plane had a thrust to weight ratio of nearly 2:1 and had to be held back by steel cables during run up to full power as its own brakes were insufficient to restrain it.
But the X-15 beat them all.  With a gross weight of 27,000 lbs and a Reaction Motors XLR99 Rocket Engine to give it a push at 70,000 lbs of thrust, it claimed a thrust to weight ratio of nearly 2.6:1!
Who knows?  Maybe there’s an Aurora driver at Area 51 reading this right now who’s getting quite a chuckle out of it as he knows something I don’t!

Nice, thank you! Would you happen to have a source handy on that Su-27? I've never heard of it and my Google-fu doesn't seem to be good enough to turn anything useful up.

Found  this here after all: http://www.angelfire.com/ab4/airplanes/Sukhoi/Record_Flanker/P42.html which sounds a lot like it.

No it should be Streak Eagle.  Look it up

Not sure the X-15 meets the "re-usable" criteria.  After each flight, they had to go find the lower tail fin and stick it back on.

"... has been the A380"? She is still operative, isn't she? Or did you try to make the answer future-proof -- given the A380 will go out of service in a decade or so? ;-)

@Roman: Link to the F-15 "Streak Eagle" at the Air Force Museum. It looks pretty plain-Jane compared to modern F-15's. :-)

The F-15E Strike Eagle was a production multi-role fighter which was never used in time to climb records as was the Streak Eagle.  It’s something entirely separate.

The GE90-115b is no longer the most powerful engine. Its world record was officially broken by its successor, the GE9X, which has indeed already flown (first flight a couple of weeks ago.) The 9X does have less rated thrust (because current 777X variants don't need as much thrust as the 777-300ER did,) but its demonstrated thrust is higher.

Can we have some metric units in the answer as well please?

I've just discovered the Scaled Composites Stratolaunch:

(Image by Robert Sullivan)
According to Wikipedia its six Pratt & Whitney PW4056 deliver 56,750 lbf/252.4 kN of thrust each, which gives it a total thrust of 340,500 lbs/1514.4 kN.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

authors: Bob Jarvis - Слава Україні


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Where is the thrust of a turbojet felt?
At a high level, this is simple. Hot gas goes out the back, and Newton's third law says the engine is pushed forwards. But when you look inside the engine, it's less clear which part experiences the thrust. Compressor? Turbine? Combustion chambers? Nozzle? How about if there's an afterburner?
For other kinds of aircraft engine, this is comparatively easy to figure out:

For a piston engine, the thrust is felt on the propeller blades, since they're doing the work on the air.
For a turboprop, most of the thrust is on the propeller blades, and the residual jet thrust presumably works like a turbojet.
For a turbofan, most of the thrust comes from the fan blades, and, again, the thrust from the hot core presumably works like a turbojet.
For a rocket, some of it comes from pressure on the head of the combustion chamber, and the rest from the divergent part of the nozzle.

Reading about turbojet history, largely in Anthony Kay's books, has shown me that compressors sometimes pull forward and turbines backwards, but hasn't shown me any rules about this. How does it work?

This is a great question with no simple answers.
When we draw the control volume around the outside of the engine, we greatly simplify things.  The thrust is the result of the change in momentum  $F_n=\dot{m}(V_j-V_i)$.  Here, we've drawn the control surface such that the pressure is the freestream pressure everywhere, so there aren't pressure contributions.
As we shrink the control volume down, things get more complicated.  If you go all the way down such that the control volume is the metal-air interface everywhere, then all the forces must resolve to pressure on the metal (except for the momentum from the mass flow of the fuel injectors, which crosses the boundary).
If you split a piece of metal -- say a compressor blade or a turbine bucket -- it will have a 'pressure side' and a 'suction side' -- but like a wing, the pressure on both surfaces may well be lower (or higher) than ambient.  I.e. one 'side' of a component may produce positive thrust -- while the other 'side' may produce negative thrust.
This becomes particularly apparent when you talk about installing an engine on an airframe.  Thrust/drag accounting -- resolving the forces to either the engine or the airframe -- is a complex matter that blurs physics with business.  We end up with concepts like cowl lip thrust and spillage drag.
When you get to these details, you have to be meticulous to make sure you are consistent -- and you communicate all of your assumptions to anyone who may use your results.  Otherwise, it is easy to mess things up.
This gets us back to the reason we like drawing the control volume where it makes the problem easy.


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Could anyone (non-military) in the present day "exceed mach 1 over a regulated area"?
There is a question What would happen if I exceeded mach 1 over a regulated area?
I wonder, could anyone in civil aviation (not military) actually carry out this violation? I know there are privately owned "warbirds", but it looks like the majority of them are really old. The "never exceed" velocity is defined well below Mach 1 for majority of these planes.
Are there any cases known where someone non-military owns an aircraft that could exceed the speed of sound and then land at least mostly in one piece?
Let's limit the scope of the question to USA and Europe.

Regardless of the "never exceed speed", it is possible for an aircraft to exceed the speed of sound, and the max speed, in a dive for example Are you asking if someone can exceed Mach 1 without exceeding the design limits of the aircraft?

Commander Worf owns a jet capable of (just) exceeding Mach 1

I mean, "land at least mostly in one piece". Design limits, I assume, are defined for the reason.

Felix Baumgartner reached Mach 1.25, jumping from an helium balloon. It happened in the US, and military wasn't involved as far as I can tell. https://en.m.wikipedia.org/wiki/Red_Bull_Stratos

Yes, In the U.S.A there are many privately owned ex-military jet fighters that are capable of exceeding Mach 1. It is quite conceivable that a privately owned fighter jet has exceeded Mach 1 but not reported it or been caught by the authorities.
You can search the FAA civil registry by type:  FAA REGISTRY
Make / Model Inquiry
Here is just a partial list of privately owned supersonic jet fighters in the United States:

Lockheed F-104
McDonnell F-4
NORTHROP F-5
MIKOYAN-GUREVICH MIG-21
MIKOYAN-GUREVICH MIG-23
MIKOYAN-GUREVICH MIG-29
Sukhoi SU-27

These two aircraft are owned by the Collings Foundation in Florida and are available for airshow demonstrations.

"It is quite conceivable that a privately owned fighter jet has exceeded Mach 1 but not reported it or been caught by the authorities." - Really? I would have assumed that all jets (especially ex-military types) would be monitored by local ATC, and they'd notice someone going Mach 1+, no?  Or is it more passive and they'd only notice that if they're actively watching that specific plane?

Maybe they could quickly try over the sea?

ATC radar wouldn't catch it, since they see ground speed and know neither your head/tail wind component nor the exact temperature at your altitude (which determines the speed of sound). If you're flying SR-71 speeds, then yeah they'd notice, but the difference between M 0.95 and M 1.05 isn't enough that they'd notice. You'd be far more likely to be "busted" based on noise complaints from the ground.

@Ralph J: And if you happened to do your flying at low level over an unpopulated area - say the Black Rock desert - you might not even show up on radar - civil, at least: IDK about military.  FTM, mach 1 has been exceeded on the ground there: https://en.wikipedia.org/wiki/ThrustSSC  Which raises the question of whether that's a violation of the FAA rule or not.  And then there are the various private suborbital spacecraft...

As much as I might dream of privately owning an SU-27, I don't think I'd be able to resist attempting maneuvers that would get me killed on the first day.

@jamesqf Mach 8 has also been exceeded on the ground. :) Granted, it was not by a private individual.

@reirab: Nor was it a manned vehicle.  And if you're going to include rocket sleds, why not rifle ammunition with supersonic muzzle velocity?  And have people call the FAA every time you go target shooting :-)

There is also 1 (sadly non-flying) English Electric Lightning in Florida!

What are the odds one of those owners hasn't done it? I know that if I had a supersonic plane, I wouldn't be able to resist. Otherwise, why spend that kind of cash? It might be worth getting caught just to have proof you did it!

I don't think the Douglas A-4 is capable of Mach 1.

You are correct. The A-4 was a subsonic aircraft but probably did sometimes exceed Mach 1.0 in a dive.

You can do it in Russia - https://migflug.com/jetflights/how-do-i-book-a-fighter-jet-flight, free bonus you will see earth from space)

No on the "see earth from space".  Only a relatively handful of flights of rocket powered aircraft throughout history have done so, and it's not yet a tourist option though that is being worked on.  See earth from above enough atmosphere that it looks a bit like being in space? perhaps.

Well yeah, i didnt go into detailes about that, but the idea holds, u will see earth from far enough to realize that it is round.

Heck you can see the earth's curvature from ground level near wendover nevada

Wait, do you mean that the earth is round? :D


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What exactly are those openings in the bellies of many jetliners?
I have circled the areas (in yellow) under the belly of the 737.
What exactly are those?
(airliners.net)

The What is: NACA duct. I'm not sure of its purpose other than to ingest air with the least possible disruption of outside airflow.

That's an air inlet -- technically a "Ram Air" inlet -- for the air conditioning packs.  There is a "left" and "right" pack, which supply air to the forward and aft part of the aircraft respectively (although either pack can supply enough air to keep the aircraft pressurized to its max altitude).  They use high temperature/high pressure bleed air from the engines or APU, but they also get airflow from the ambient air which is used to cool the bleed air.  The inlet noted in the question is where the ambient air enters, and there are exhaust vents for this air on the bottom of the aircraft.  THIS air isn't used for the pressurization per se (i.e. it doesn't enter the cabin), but just for cooling the air that will enter the cabin (which came from the compressor in the engines/APU, upstream of the combustion chamber).
On the ground, there are louvers that close to keep water and debris out of these ducts, and fans are used to pull in air in that configuration.  In-flight, the louvers open and airflow is generally sufficient to move the air through the system (although the fans still provide some assist).
While there is some amount of drag here, it's fairly minimal, and the ability to keep the cabin pressurized and cool is sufficiently important that the little bit of drag that's caused here is considered acceptable.
Close-up photo of the inlet door (Next-Gen 737):

Close-up photo of the inlet door (Classic 737):

Photo of exhaust louvers:

source page for all of the above (with technical discussion of the air conditioning & pressurization system): http://www.b737.org.uk/airconditioning.htm
Even more technical description of the system -- text & schematics but no photos

Funny how the brain can fill in blanks that don't exist.  I read that as a photo of the exhaust lovers.  Mind you, I do feel odd in loving the smell of burnt AvTur.

This specific inlet type is called a "NACA inlet", "NACA scoop" or "NACA duct", since it had been invented by Francis Melvin Rogallo at NACA in 1941 (PDF) and refined by scientists at NACA (now NASA) Ames. Its main advantage is its simplicity: It just needs a properly shaped cutout in the skin and a rounded rear edge, whereas the airscoops it replaces need carefully shaped contours.
The working principle is quite similar to that of a delta wing, only in this case the actual wing is missing, and is surrounded by sheet metal. But like on the swept leading edge of a delta wing, the swept left and right edges create a vortex which is swallowed by the actual intake at the rear of the cutout. This helps to create a lot of flow for the given area, even though efficiency is below that of a well-shaped airscoop.